Merjenje hitrosti in pretoka vode z metodo razredčenja in metodo slikanja delcev

Fink, Uroš (author), Kobal, Milan (mentor)

Na vodotokih po severu in severozahodu Slovenije smo opravili meritve hitrosti toka vode in pretokov z metodo razredčenja in metodo slikanja delcev. Z navedenima metodama smo pridobili podatke, ki smo jih uporabili pri testiranju natančnosti uporabljenih metod. Pri uporabi metode razredčenja smo v vodotoke na merilnih odsekih vlivali solno raztopino NaCl in vode, ki je v vodotoku ustvarila oblak raztopine, ki se je z tokom vodotoka premikal proti merilni sondi, ki smo jo namestili nižje po vodotoku. Oblak solne raztopine ima drugačno elektro prevodnost kot preostala voda, ki je v vodotoku prisotna naravno. To sprememba v elektro prevodnosti nam omogoča, da na merjenem vodotoku izmerimo hitrost in pretok vodotoka. Pri uporabi metode slikanja delcev smo merjene vodotoke najprej z daljinsko vodenim letalnikom posneli iz zraka. Tako pripravljene posnetke smo analizirali z algoritmom HydroSTIV, ki na posnetkih prepozna spremembe vrednosti slikovnih celic med vsako od posnetih sličic posnetka. Na podlagi ugotovljenih sprememb kot rezultat pridobimo hitrost vode v vodotoku. Na terenu zajete podatke in z metodo slikanja delcev pridobljene hitrosti smo uporabili v regresijskih analizah z namenom, da ugotovimo ali je natančnost meritev primerna za njihovo širšo uporabo na terenu. Rezultati so pokazali, da sta metodi zanesljivi in da z njuno uporabo pridemo do zanesljivih rezultatov, ki lahko v nekaterih okoliščinah dopolnijo ali pa nadomestijo metode, ki se za merjenje hitrosti in pretokov vodotokov bolj razširjeno uporabljajo danes.

• Language: Slovenian
• Keywords: daljinsko vodeni letalnik, metoda slikanja delcev, metoda razredčenja, solna raztopina, pretok, vodotoki, regresija, Reynoldsovo število
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [U. Fink]
• Year: 2025
• PID: 20.500.12556/RUL-170567
• UDC: 630*38:630*58(043.2)=163.6
• COBISS.SI-ID: 242444547
• Publication date in RUL: 10.07.2025

Secondary language

• Language: English
• Title: Velocity and flow measurements using the dilution method and particle image velocimetry

Abstract

We conducted discharge and velocity measurements on waterways scattered across northern and northwestern Slovenia by using the dilution method and particle image velocimetry. by using the aforementioned methods we acquired data that was later used in determining the accuracy of the used methods. A salt solution of NaCl was injected into the waterways that formed a tracer cloud which moved with the water current towards a measuring probe that was placed downstream from the injection site. The electrical conductivity of the tracer cloud is different from the naturally present water in the waterway. This change in electrical conductivity allowed us to measure the discharge and speed of the water. For the purposes of performing particle image velocimetry we first recorded aerial footage of selected waterway by using a camera mounted on a unmanned aerial vehicle. The acquired footage was then processed using the HydroSTIV algorithm, which recognizes changes in pixel values on the footage and determines the water speed based on that change. Both measured and calculated data was used in statistical analyses with the purpose of determining their accuracy and their suitability for wider use in field measurements. The results showed both methods to be reliable and can be used to acquire accurate field data. Data acquired in this way can be used for supplementation of other methods of discharge and speed measurements or be used as a replacement for methods that see wider use today.

• Keywords: unmanned aerial vehicle, particle image velocimetry, dillution method, salt dillution, discharge, waterways, regression, Reynolds number